A variety of meat tenderizing machines are known and some including rolls of knives wherein pieces of meat are fed therethrough by actuating the rolls of knives. Such machines usually can handle only small pieces of meat and also cannot handle thick pieces and are dangerous to the operator's fingers. More recently, machines have been developed which comprise a block of narrow cutting blades supported above a meat support platform and which are actuated to penetrate a piece of meat positioned thereunder whereby to tenderize the meat. The meat is usually oriented with the tendons or connecting tissues in the meat transverse to the flat cutting edges of these blades whereby to cut these tendons and tissues. An example of such a machine is described in U.S. Pat. No. 5,525,102, issued on Jun. 11, 1996. As therein described a piece of meat is positioned on a sliding board whereby the piece of meat can be positioned under a block of cutting blades which are actuated to penetrate the meat. A disadvantage of such a machine is that it can only handle small pieces of meat which is movable in a single plane only and there is also danger to the hand of an operator which is required to displace the sliding board with the meat thereon in the vicinity of the block of cutting blades. Also, this machine is extremely slow in operation and can only handle pieces of meat which are no wider than the board's width or of the block of cutting blades. Further, if the meat piece is repositioned to try and tenderize portions not penetrated by the blades, then the piece of meat is not uniformly tenderized. Such a machine is also manual and the blades therefore do not protrude in the meat at the same constant force as this is dependent on the hand force that the operator applies when biasing the block of blades against and into the piece of meat being tenderized. There is the risk that the operator could use one hand to actuate the block of blades and the other hand to displace the piece of meat under the block thereby placing his hand in danger of being cut by the blades.